[@Zugzwang] I like your thoughts on coming from the west, maybe the NCR sends an envoy to the Eastern Brotherhood. The upper east coast has dealt with most of the raider problem and brought a lot of settlements together though the Minutemen and Brotherhood protection. 

The Mid-west Brotherhood is more like the East coast chapter, granted they have working vehicles somehow. Very few of them but they do have some. So I don't see why the NCR couldn't get some jeeps working or even little armored troop carrier. 

[@Zetsuko] Thanks for the interest.